“无中生有”的意思是本来没有的事，被人凭空说出来或编造出来。

The meaning of "无中生有" is something that originally didn't exist but is fabricated or made up by someone out of thin air.

这个成语常用来说别人造谣、说假话，让人生气。

This idiom is often used to describe someone spreading rumors or telling lies, which makes people angry.